Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites

Research output: ThesisDissertationMonograph

Abstract

Thermoplastic composite materials based on renewable raw materials are promoted globally in various ways. They can be prepared as durable, but biodegradable materials as poly(lactic acid) (PLA) ligno-cellulose composites are. Their advantages are their absence of fossil carbon, material recyclability, conversion to products using normal thermoplastic converting methods, absence of microplastic formation due to their biodegradability and haptic, unplastic-like feeling. The most important issue in tailoring PLA ligno-cellulosic fibre composites is to control the interfacial connections between fibre and polymer and porosity. The main components affecting the interface are fibre length, fibre aspect ratio, fibre surface roughness and surface chemistry, fibre modification and additives used in composite such as plasticisers and coupling agents. In injection-moulded products and especially with short wood fibres, the fibre length is usually below the critical fibre length needed for fibre reinforcement. This is due to fibre degradation occurring in typical thermoplastic processing at high temperatures. Compounding followed by injection moulding were the main processing methods also used in this study. The main aims of this research are to prove that regardless of the fibre dimensions of ligno-cellulosic wood fibre PLA composites, there is a need to couple between fibre and polymer to obtain optimal properties for the composite. It is also suggested that especially suitable coupling agents are oils from renewable origin and especially from modified oils such as epoxidised linseed oil (ELO) which can provide coupling between fibre and a polymer matrix. The conclusions of this research are the following: The fibre-polymer bonding was improved and the porosity of the material reduced in PLA composites with cellulose nanofibres (CNF), high consistency nanocellulose (HefCel), micro-cellulose (MC) and bleached softwood kraft pulp (BSKP) with ELO addition on fibre. The improved fibre dispersion with nanocelluloses, especially with HefCel was found due to ELO addition. The coupling of fibre and polymer was proved by FTIR analysis, by increased melt viscosity and by improved mechanical performance due to ELO addition to compounds.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Lappeenranta University of Technology
Supervisors/Advisors
  • Koiranen, Tuomas, Supervisor, External person
  • Kärki, Timo, Supervisor, External person
Award date23 Nov 2018
Publisher
Print ISBNs978-952-335-288-9
Electronic ISBNs978-952-335-289-6
Publication statusPublished - 23 Nov 2018
MoE publication typeG4 Doctoral dissertation (monograph)

Fingerprint

Lactic acid
Cellulose
Fibers
Composite materials
Thermoplastics
Coupling agents
Polymers
Wood
Porosity
Kraft pulp
Softwoods
Biodegradability
Plasticizers
Fiber reinforced materials
Nanofibers
Processing
Surface chemistry
Polymer matrix
Injection molding

Keywords

  • polylactic acid
  • PLA
  • cellulose
  • ligno-cellulose fire
  • epoxidised linseed oil
  • biocomposite
  • bleached softwood kraft pulp
  • fibre composite

Cite this

Immonen, Kirsi. / Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites. Lappeenranta University of Technology, 2018. 115 p.
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title = "Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites",
abstract = "Thermoplastic composite materials based on renewable raw materials are promoted globally in various ways. They can be prepared as durable, but biodegradable materials as poly(lactic acid) (PLA) ligno-cellulose composites are. Their advantages are their absence of fossil carbon, material recyclability, conversion to products using normal thermoplastic converting methods, absence of microplastic formation due to their biodegradability and haptic, unplastic-like feeling. The most important issue in tailoring PLA ligno-cellulosic fibre composites is to control the interfacial connections between fibre and polymer and porosity. The main components affecting the interface are fibre length, fibre aspect ratio, fibre surface roughness and surface chemistry, fibre modification and additives used in composite such as plasticisers and coupling agents. In injection-moulded products and especially with short wood fibres, the fibre length is usually below the critical fibre length needed for fibre reinforcement. This is due to fibre degradation occurring in typical thermoplastic processing at high temperatures. Compounding followed by injection moulding were the main processing methods also used in this study. The main aims of this research are to prove that regardless of the fibre dimensions of ligno-cellulosic wood fibre PLA composites, there is a need to couple between fibre and polymer to obtain optimal properties for the composite. It is also suggested that especially suitable coupling agents are oils from renewable origin and especially from modified oils such as epoxidised linseed oil (ELO) which can provide coupling between fibre and a polymer matrix. The conclusions of this research are the following: The fibre-polymer bonding was improved and the porosity of the material reduced in PLA composites with cellulose nanofibres (CNF), high consistency nanocellulose (HefCel), micro-cellulose (MC) and bleached softwood kraft pulp (BSKP) with ELO addition on fibre. The improved fibre dispersion with nanocelluloses, especially with HefCel was found due to ELO addition. The coupling of fibre and polymer was proved by FTIR analysis, by increased melt viscosity and by improved mechanical performance due to ELO addition to compounds.",
keywords = "polylactic acid, PLA, cellulose, ligno-cellulose fire, epoxidised linseed oil, biocomposite, bleached softwood kraft pulp, fibre composite",
author = "Kirsi Immonen",
year = "2018",
month = "11",
day = "23",
language = "English",
isbn = "978-952-335-288-9",
series = "Acta Universitatis Lappeenrantaensis",
publisher = "Lappeenranta University of Technology",
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school = "Lappeenranta University of Technology",

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Immonen, K 2018, 'Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites', Doctor Degree, Lappeenranta University of Technology .

Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites. / Immonen, Kirsi.

Lappeenranta University of Technology, 2018. 115 p.

Research output: ThesisDissertationMonograph

TY - THES

T1 - Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites

AU - Immonen, Kirsi

PY - 2018/11/23

Y1 - 2018/11/23

N2 - Thermoplastic composite materials based on renewable raw materials are promoted globally in various ways. They can be prepared as durable, but biodegradable materials as poly(lactic acid) (PLA) ligno-cellulose composites are. Their advantages are their absence of fossil carbon, material recyclability, conversion to products using normal thermoplastic converting methods, absence of microplastic formation due to their biodegradability and haptic, unplastic-like feeling. The most important issue in tailoring PLA ligno-cellulosic fibre composites is to control the interfacial connections between fibre and polymer and porosity. The main components affecting the interface are fibre length, fibre aspect ratio, fibre surface roughness and surface chemistry, fibre modification and additives used in composite such as plasticisers and coupling agents. In injection-moulded products and especially with short wood fibres, the fibre length is usually below the critical fibre length needed for fibre reinforcement. This is due to fibre degradation occurring in typical thermoplastic processing at high temperatures. Compounding followed by injection moulding were the main processing methods also used in this study. The main aims of this research are to prove that regardless of the fibre dimensions of ligno-cellulosic wood fibre PLA composites, there is a need to couple between fibre and polymer to obtain optimal properties for the composite. It is also suggested that especially suitable coupling agents are oils from renewable origin and especially from modified oils such as epoxidised linseed oil (ELO) which can provide coupling between fibre and a polymer matrix. The conclusions of this research are the following: The fibre-polymer bonding was improved and the porosity of the material reduced in PLA composites with cellulose nanofibres (CNF), high consistency nanocellulose (HefCel), micro-cellulose (MC) and bleached softwood kraft pulp (BSKP) with ELO addition on fibre. The improved fibre dispersion with nanocelluloses, especially with HefCel was found due to ELO addition. The coupling of fibre and polymer was proved by FTIR analysis, by increased melt viscosity and by improved mechanical performance due to ELO addition to compounds.

AB - Thermoplastic composite materials based on renewable raw materials are promoted globally in various ways. They can be prepared as durable, but biodegradable materials as poly(lactic acid) (PLA) ligno-cellulose composites are. Their advantages are their absence of fossil carbon, material recyclability, conversion to products using normal thermoplastic converting methods, absence of microplastic formation due to their biodegradability and haptic, unplastic-like feeling. The most important issue in tailoring PLA ligno-cellulosic fibre composites is to control the interfacial connections between fibre and polymer and porosity. The main components affecting the interface are fibre length, fibre aspect ratio, fibre surface roughness and surface chemistry, fibre modification and additives used in composite such as plasticisers and coupling agents. In injection-moulded products and especially with short wood fibres, the fibre length is usually below the critical fibre length needed for fibre reinforcement. This is due to fibre degradation occurring in typical thermoplastic processing at high temperatures. Compounding followed by injection moulding were the main processing methods also used in this study. The main aims of this research are to prove that regardless of the fibre dimensions of ligno-cellulosic wood fibre PLA composites, there is a need to couple between fibre and polymer to obtain optimal properties for the composite. It is also suggested that especially suitable coupling agents are oils from renewable origin and especially from modified oils such as epoxidised linseed oil (ELO) which can provide coupling between fibre and a polymer matrix. The conclusions of this research are the following: The fibre-polymer bonding was improved and the porosity of the material reduced in PLA composites with cellulose nanofibres (CNF), high consistency nanocellulose (HefCel), micro-cellulose (MC) and bleached softwood kraft pulp (BSKP) with ELO addition on fibre. The improved fibre dispersion with nanocelluloses, especially with HefCel was found due to ELO addition. The coupling of fibre and polymer was proved by FTIR analysis, by increased melt viscosity and by improved mechanical performance due to ELO addition to compounds.

KW - polylactic acid

KW - PLA

KW - cellulose

KW - ligno-cellulose fire

KW - epoxidised linseed oil

KW - biocomposite

KW - bleached softwood kraft pulp

KW - fibre composite

M3 - Dissertation

SN - 978-952-335-288-9

T3 - Acta Universitatis Lappeenrantaensis

PB - Lappeenranta University of Technology

ER -

Immonen K. Ligno-cellulose fibre poly(lactic acid) interfaces in biocomposites. Lappeenranta University of Technology, 2018. 115 p.